Sacrificial screen

Tests of sacrificial anode materials are generally conducted for three reasons for screening (or ranking), performance information and quality control. 

The application of sacrificial anodes for the protection of structures requires the development of suitable anode materials for the exposure environment. Screening tests enable the rapid selection of materials which show potential as candidates for the given application. These tests may typically use a single parameter (e.g. operating potential at a defined constant current density) as a pass/fail criterion and are normally of short duration (usually hours) with test specimen weights of the order of hundreds of grams. The tests are not intended to simulate field conditions precisely. 

The use of sacrificial anodes in circulating water systems is limited to the application of cathodic protection to stop gates, coarse screens and other plant that are readily accessible so that the anodes can be replaced when they are consumed. Such anodes are not normally used in condensers, pumps and auxiliary coolers for the following reasons ... 

Sacrificial anodes frequently are used to protect the rotating steel frame which supports the Monel screens at the plant intake. 

Experience has shown that at the end of our sled deployment, the axle on the sled will spin faster than material can be deployed. When this occurs, the anode unravels or tears inside the sled and can jam, resulting in damage to the anode. As a preventative measure, we attach approximately 1 m of sacrificial fiberglass screen to the anode end that will deploy last. This is the end furthest from the underwater cable. The screen is perforated at the connection to the anode to ensure detachment of the screen from the anode if mechanical stress due to jamming is encountered. Step-by-step procedures... 

Wei, Y, et al., 2013. Screen printing of a capacitive cantilever-based motion sensor on fabric using a novel sacrificial layer process for smart fabric applications. Meas. Sci. Technol. 24 (7), 75104. 

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